Historically, flexible intermediate bulk containers (bulk bags) have been used for receiving, storing, transporting and discharging flowable materials of all types. Bulk bags are typically constructed in square, vertically rectangular, or circular shapes with lift straps attached to each of the uppermost corners of the square, rectangle or circle.
By way of example, flexible intermediate bulk containers are used for handling flowable materials in granular or powder form such as chemicals, minerals, fertilizers, foodstuffs, grains and agricultural products, etc. The advantages of such receptacles include relatively low weight, reduced cost, versatility and, in the case of reusable receptacles, low return freight costs.
U.S. Pat. No. 4,903,859 discloses a bulk bag adapted for use with liquids. The bulk bag of the '859 patent comprises four double layer side walls. Stiffeners formed from cardboard are inserted between the layers of the side walls thereby imparting sufficient rigidity to the container to permit its use with liquids. Although the bag of the '859 patent has been generally well received, its utilization is somewhat limited by the fact that it cannot be stacked to facilitate the transportation and storage of the bags and the contents thereof.
The present invention comprises an improved bulk bag design which overcomes the foregoing and other problems long since associated with the prior art. In accordance with the broader aspects of the invention, a bulk bag comprises four double layered side walls. The side walls receive stiffener panels which are formed from wood. Sleeves provided at each corner of the bulk bag receive stiffener rods also formed from wood. The bulk bag is provided with a double layered top which also receives a stiffener panel formed from wood.
When the bulk bag of the present invention is used to receive, store, transport and discharge liquids, it is typically provided with a liner comprising film formed from a plastic material such as polyethylene. In such instances, the bulk bag may be provided with baffles extending diagonally across each interior corner of the bulk bag to prevent the liner from pinching into the corners. When used, the baffles are preferably provided with stiffener panels formed from wood.
In accordance with another aspect of the invention, double layer dividers extend across the interior of the container from the midpoints of the side walls, thereby dividing the interior of the container into four quadrants. When employed, the divider panels are preferably provided with stiffener panels formed from wood.
The use of the present invention is highly advantageous in receiving, storing, transporting, and discharging liquids. For example, the present invention is readily adapted to receiving, storing, transporting and discharging orange juice, tomato paste, and other foodstuffs. Containers constructed in accordance with the invention are adapted for stacking. For example, certain embodiments of the invention can be stacked one on top of the other to a total height of six containers. The stackability of the container of the present invention is highly advantageous in facilitating transportation and storage of the containers and the materials contained therein.